Creating Believable Materials - Photographic Rendering with V-Ray for SketchUp - page 195

Note
16- and 32-bit images belong to a category of image file formats known as float-
ing point. These files, which include the HDR and EXR formats, store their pixel
information in floating point values.
Now, the term floating point refers to the fact that the decimal point in a group of
numbers can float, meaning it can be placed anywhere relative to the significant
digit(s) of the number. For instance, a number with a significant digit such as 1
can be used to represent differing values such as 1.1, 1.01, and 1.001.
This in turn means that these file types are capable of holding significantly more
pixel information than their 8-bit cousins, indeed significantly more than what our
current crop of computer display devices are capable of showing.
This again in turn means that when working in a post-processing environment,
16- and 32-bit images give a compositing artist greater latitude regarding the
types and strength of edits that can be made.
This means I have a fairly specific setup to work with and one that I will share with
you now. In the V-Ray option editor, in the Color mapping rollout, we need to make
a number of changes by performing the following steps:
1. Disable the Linear workflow option.
2. Uncheck the Affect background control.
3. Then, as a final tweak in this rollout, enable the Don't affect colors (adap-
tion only) feature.
Note
Unchecking Affect background does exactly as the name suggests and
stops anything we do in the color mapping controls from affecting the im-
age being rendered in the background, which means we can exercise
separate control over that as we want or need.